The present invention relates to an aircraft towing vehicle and more particularly to an aircraft towing vehicle employing rigid hitch arms and coordinated all-wheel steering.
In the field of aircraft towing, spotting and handling on the ground, it has been the general practice to employ a tractor in combination with a tow bar to move aircraft. Although such devices have served the purpose, they have not proved entirely satisfactory under all conditions of service because of the substantial length and complexity of the three-component train composed of the tractor, tow bar and aircraft, including two articulating joints, the aircraft-wheel and the tractor pintle hook. This arrangement is often too long and unwieldy, requiring considerable maneuvering area and a highly skilled driver, especially when pushing the aircraft. The length of this train makes it undesirable for use aboard aircraft carriers and in restricted spaces. Furthermore, tow bars suffer from a high damage rate and are a major expense.
Another exemplary prior art device, called the "spotting dolly," has also been used to move and spot aircraft. The spotting dolly has a large cut-out in one end to accommodate hydraulically powered lift arms which engage and lift the aircraft nose or tail wheel, which the spotting dolly wheels straddle. However, the spotting dolly has not proven entirely satisfactory under all conditions of service because the spotting dolly body must straddle the aircraft nose or tail wheel, so that the vehicle is restricted in height in order to accommodate most aircraft. This height restriction limits the size, power and drawbar pull of the spotting dolly, since available low profile engines are of limited power. In addition, the spotting dolly cannot attach to deeply recessed wheels under low fuselage aircraft. Furthermore, there is a possibility of aircraft wheel droppage, and an imposed download which is often much greater than the total vehicle weight.